1. Field of the Invention
The present invention relates to a delivering equipment having heat insulating function and in more detail, to a delivering equipment used in delivering and/or storing articles such as food which is needed to be under desired temperature. Preferably, the equipment of the present invention is used in an aircraft.
2. Description of the Prior Art
This kind of container has been generally used which is provided with means for heating or refrigerating food stored in the receptacle thereof. One of those has been proposed by the applicant of the present invention wherein the receptacle is provided with the concave for storage of heat generating means. The bottom of the concave is found with the hole communicating the concave with another container which has the same construction and is positioned under the former container (Japanese Utility Model Publication No. 18986/1982). With respect to heat generating material contained in the heat generating means generally known is one with, for example, polyethylene glycol as its main content (refer to Japanese Patent Publication No. 53375/1981) or stearyl alcohol as its main content.
However, the container of the type disclosed in Japanese Utility Model Publication No.18986/1982, which is provided with heat generating means producing heat by oxidizing reaction of heat generating material therein, requires provision of the through hole conveying air to the heat generating means, which causes the problem of decrease in the effective capacity of the container.
On the other hand, it is known that preservation of food is preferably carried out in the condition of below 10.degree. C. or over 65.degree. C. Where food is preserved under a high temperature, inside of the insulated receptacle of the container must be heated to be maintained in the temperature of over 65.degree. C. However, where polyethylene glycol or stearyl alcohol is used as a main heat generating material of the heat generating means, solidification point thereof is relatively low (about 59.degree. C. in case of steary alcohol, whereas about 55.degree. C. in case of polyethylene glycol) and therefore, it is difficult to obtain heat capacity sufficient for preservation of food in a high temperature over 65.degree. C. In other words, the portion around heat generating means within the insulated receptacle may be maintained at over 65.degree. C. whereas the temperature of corners of the receptacle is by about 6.degree. C.-7.degree. C. lower than that in the portion around heat generating mans and can be less than 65.degree. C.
Further, in the conventional container, heat generated from the heat generating means is transmitted by convection, which causes a difference in heat distribution within the container. The result is that unless heat capacity of heat generating means is increased sufficiently, inside of the container cannot be maintained in a desired temperature range, which creates a problem of decrease in cost-efficiency and effective capacity of the container.